Fork lift for garden tractor



Oct. .1962 H. A. ROBINSON 3,06 ,1 6

FORK LIFT FOR GARDEN TRACTOR Filed 5 1960 4 Sheets-Sheet 1 Harry A.Robinson 1 N VEN TOR.

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United States Patent Office 3,061,126 Patented Oct. 30, 1962 3,061,126FORKLIFT FOR GARDEN TRACTOR Harry A. Robinson, 2625 Johnson St.,Eikhart, Ind. Filed May 5, 1960, Ser. No. 26,994 8 Claims. (Cl. 214-672)This invention relates to a fork lift mechanism that may be attachedto'any garden tractor including all the controls necessary for properoperation of the lift fork.

A primary object of this invention therefore, is to provide aself-contained fork lift mechanism that is readily adaptable to all fourwheel garden tractors.

It is a further object of this invention, to provide a fork liftmechanism which is simple to operate and yet accurately controlled.

Another object of this invention in accordance with the foregoingobjects, is to provide a fork lift mechanism which is powered from thevehicle to which it is attached and capable of simple and accuratecontrol with little modification of the vehicle structure.

In accordance with the foregoing objects, the lifting fork mechanism inaccordance with this invention includes a frame on which the fork memberis vertically moved upwardly or downward-1y, said frame being pivotallyconnected at a forward end of the tractor, its position on the tractorbeing controlled by a positioning lever which cooperates with astationary rack mounted on the vehicle to hold the frame in any adjustedposition. A forward and'reverse gear box is secured to the frame at thebottom thereof and has a power shaft extending out therefrom at one orthe other side for driving connection to the tractor motor by means of abelt and pulley drive, with a belt tightener including an idler pulleyyieldably maintaining the belt under tension for all positions of thefork frame, avoiding thereby any slackening of the belt. The gear boxincludes a pair of opposing gears rotatively fast with the power shaftbut slidable with respect thereto, said gears being selectivelyengageable with an output gear connected to an output shaft extendingfrom the top of the gear box, said output shaft being a screw shaftwhich is threadedly engaged with the fork so as to raise or lower thefork on the frame upon forward or reverse rotation of the output screwshaft. In order to control the drive of the gear box for forward,neutral and reverse, the opposing gears slidable on the power shaft aremovable by means of a cam actuated yoke, said cam being connected to acontrol shaft extending out of the gear box rearwardly thereof, saidcontrol shaft being connected by means of a lever and link to a controllever pivotally mounted on the frame adjacent the top thereof.

These together with other objects and advantages will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings. I

FIGURE 1 is a side elevational view of the forklift mechanism mounted ona garden tractor in accordance with this invention, with parts of thetratcor being broken away. FIGURE 2 is a partial side elevational viewfrom the other side of the tractor.

FIGURE 3 is a rear view of the gear box as mounted on the fork liftframe.

FIGURE 4 is a front view of the fork lift and frame.

FIGURE 5 is a side view with parts shown in section, of the fork liftand frame. 7

FIGURE 6 is a sectional view taken through a pla indicated by sectionline 66 in FIGURE 4.

FIGURE 7 is a sectional view taken through a plane indicated by sectionline 7--7 in FIGURE 5.

FIGURE 8 is an enlarged partial view of the-fork lift and frame.

FIGURE 9 is a sectional view taken through a plane indicated by sectionline 9-9 in FIGURE 8.

FIGURE 10 is a top section view of the forward and reverse gear box.

FIGURE 11 is a rear section view of the forward and reverse gear box.

Referring now to the drawing in detail, the fork lift assembly generallyindicated by reference numeral 10 is shown mounted on a tractor vehicle12 in FIGURE 1. The tractor 12 includes a power unit 14 from which thepower is derived for raising and lowering the fork lift as more clearlyseen in FIGURE 2. A control lever 16 is provided for controlling thepivotal position of the fork lift frame on the vehicle, while thecontrol lever 18 is provided for controlling the direction of movementof the fork lift on the frame. It will therefore be apparent, that thetwo control levers 16 and 18 being the only controls necessary foroperation of the fork lift mechanism, are within easy grasp of thedriver of the tractor seated on seat 2th of the vehicle 12.

The lift fork assembly includes a lift fork 22 which is slidably mountedon a lift fork frame 24. Referring to FIGURES 4, 5, 6, 7, 8 and 9, itwill be seen that the lift fork 22 includes a pair of vertical members26 and 28 interconnected by a pair of horizontal members 30 and 32forming a rigid fork 22. Connected to the horizontal members 30 and 32intermediate the vertical members 26 and 28 is .a slide member 34.

The slide member 34 is guidingly supported by the frame 24 by mean-s ofrollers 36 and 38 rotatably mounted on the slide member 34 by means ofinwardly extending portions 40, such guide rollers being secured to theslide member 34 adjacent to the two connections of the slide member 34to the horizontal fork members 30 and 32. The rollers are supported on ashaft 42 journaled within portions 40 of the slide 34. The guide rollers36 and 38 move within tracks 44 and 46 formed in the shaft 48 isthreadedly engaged with a nut member 54 as:

more clearly seen in FIGURES 6, '7 and 5. The nut member 54 is connectedto the fork lift 22 by being connected to 'a bracket member 56 which isconnected by means of bolt 58 to a bracket member 60 which is welded orotherwise secured to the slide member 34 of the fork 22. Accordingly,upon rotation of the screw shaft 48 in one direction or the other, thefork will be caused to move upwardly or downwardly relative to the frame24. g -The screw shaft 43 is therefore driven in both directions bymeans of a gear box 62 attached adjacent to a lower end of the frame 24with the screw shaft 4st.- tending into the gear box at the top thereof.As seen in FIGURES 5 and ll,'the lower end of the screw shaft 48 isconnected to a bevelgear 64 located within the gear box 62. Arrangedperpendicularly to the screw shaft 48 and extending outwardly fromeither side of the gear box 62, is a power shaft 66. Slidably mounted onthe power shaft but rotatively fast therewith, are a pair of opposedbevel gears 63 and 70 which when meshing with output gear 64 will driveit in one or the other direction. The power shaft 66 has a drivingpulley wheel '72 connected thereto, said pulley wheel 72 capable ofbeing attached to the power shaft 66 on either side of the gear box 62depending upon which side a power take-0E from the tractor power unit isavailable.

In order to control the drive of the output screw shaft 48 and alsodisengage it from drive completely, a for ward and reverse control cam74 is provided as seen in FIGURE 11, said cam being connected to acontrol shaft 76 extending outwardly from the gear box 62 to the rearthereof as seen in FIGURE 10. Slidably mounted on the power shaft 66, isa yoke member 78 as seen in FIG- URES and 11 having lateral sides 80 and82 which are engageable with the opposing bevel gears 68 and 70 forshifting thereof in one or the other direction. As seen in FIGURE 11,the cam 74 is in a neutral position wherein the yoke follower member 78has positioned-both gears 68 and 70 out of engagement with the outputbevel gear 64. Upon rotation of the cam 74 in one or the other directionfrom the neutral position shown in FIG- URE 11, one or the other of thebevel gears 68 and 70 will be in mesh with the output gear 64 to rotatethe screw shaft 48 to thereby raise or lower the fork as hereinbeforeexplained. Connected to the cam control shaft 76 just at the rear of thegear box 62, is a control lever 84 having a pivot connection 86 at oneend thereof as shown in FIGURE 10. It should of course be realized thatthe pivot connection may be placed at the other end of the lever 84 ifit is desired to control the lever from said other end. As more clearlyseen in FIGURES 1 and 3, the control lever 84 is connected by means of alink 86 to the control lever 18, said control lever 18 also having aguide bar 88 connected thereto which is slidably mounted on the frame 24for limiting the movement of the lever 18 between its control positions.

The forward and reverse gearing is connected to the tractor power source14 by means of a belt and pulley drive as more clearly seen in FIGURE 2.The drive pulley 72 connected to the gear box power shaft 66 isdrivingly connected to a pulley take-off from the power unit 14, saidtake-01f pulley 90 and drive pulley 72 having a flexible belt 92 trainedthereover. It will be appreciated, that inasmuch as the gear box 62mounting the drive pulley 72, is secured to the fork lift frame 24,pivotal movement of the frame 24 may tend to slacken or tighten thepulley belt 92. Accordingly, a belt tightener is provided in order tomaintain the belt 92 under tension for all positions of the frame 24 andgear box 62, said belt tightener including an idler pulley 94 which isrotatably mounted on a frame 96 said frame 96 being pivotally mounted onthe frame 24 and biased upwardly by means of spring 98 so as to tensionthe belt 92 engaged with the idler pulley 94.

The fork frame 24 is pivotally mounted on the vehicle 12 by means ofpivot connection 100. The frame 24 is also connected to the controllever 16 by means of link 102 as shown in FIGURE 1. The lever 16therefore controls the pivotal position of the fork frame 24, said lever16 being pivotally connected to the vehicle 12 at pivot connection 104while the lever is held in adjusted position by means of a releasabledetent 106 actuated by a finger button 108, said detent 106 cooperatingwith an arcuate rack member 110 fixed to the vehicle frame in anysuitable manner.

From the foregoing description, operation of the lift fork mechanismwill be apparent. The tractor driver in order to engage and lift a loadfor carrying it away, will atcuate the control lever 16 to tilt the forkframe 24 forwardly for engaging the bottom of the load with the forkblades 22. The tractor is then moved forwardly to engage the load on thefork 22. After positioning the load on top of the lift fork 22, thedriver again engages the control lever 16 to tilt or pivot the frame 24backwardly so as to hold the load on the fork 22. Then, the driver willengage the control lever 18 which has been in neutral position up tillnow, and cause drive of the screw shaft 48 in one direction in order toraise the fork 22 on the frame 24 to a predetermined height and thenreturn the lever to neutral position for holding the load at saidheight. The load is thereby lifted and carried by the tractor and may besubsequently lowered and left in a desired position.

It will also be apparent from the foregoing description, that a minimumof vehicle modification is required in order to mount the fork liftmechanism thereon, and that after mounting it will be observed that thecontrol levers 18 and 16 are in positions within ready grasp of thevehicle driver.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. A fork lift attachment for a garden tractor type vehicle comprising,frame means pivotally mounted at a forward end of the vehicle, forkmeans slidably mounted on said frame means, forward and reverse gearmeans mounted on said frame means independently of the vehicle andoperatively connected to said fork means for slidable movement thereofin both directions, transmission means displaceably mounted on saidvehicle and operatively connecting said gear means to a source of powerfor all adjusted positions of the frame means, and mechanical forkcontrol means mounted on the vehicle and operatively connected to saidframe means for adjusting the pivotal position of the frame means andfork means relative to the vehicle.

2. The combination as defined in claim 1, including single gear controlmeans operatively connected to said gear means for selectiveconditioning of said gear means in forward, neutral and reverse, saidgear control means including a lever pivotally connected to said framemeans extending rearwardly of the vehicle adjacent to the fork controlmeans.

3. The combination as defined in claim 2, wherein said gear meansincludes a gear box secured to said frame means, a power shaft journaledin said gear box and operatively connected to said transmission means,forward and reverse gears slidably connected to said power shaft and cammeans connected to said gear control means for selectively moving saidgears into mesh with an output gear operatively connected to said forkmeans.

4. The combination as defined in claim 3, wherein said transmissionmeans includes a wheel connected to said power shaft, an endlessflexible belt drivingly connecting said Wheel to said power source and abelt tightener mounted on the vehicle and maintaining said belt undertension for all positions of the frame means.

5. The combination as defined in claim 4, wherein said fork controlmeans includes a control lever pivotally mouted on the vehicleintermediate the ends thereof and link connected to said frame means.

6. The combination as defined in claim 1, wherein said transmissionmeans includes a flexible endless belt drivingly connecting said gearmeans to said power source and a belt tightener maintaining said beltunder tension in all positions of said frame means.

7. A material handling device for a mobile frame comprising, anelongated upright guide frame, means pivotally securing a lower end ofsaid guide frame to a forward end of said mobile frame, an elevatablecarriage movably disposed in said guide frame, a pair of lift armsprojecting forwardly of said carriage, an arcuate rack member carried bysaid mobile frame, a control lever pivotally mounted on said mobileframe and releasably engageable with said arcuate rack member forholding thereof in control positions, an upwardly and forwardlyprojecting link pivotally connected between said control lever and guideframe above said pivotal securing means, motor means, a belt tighteningpulley pivotally mounted on said guide frame, a second drive pulleycarried adjacent said lower end of the guide frame, an endless beltextending from said motor means about said pulleys and a reversing drivemounted on said guide frame for pivotal displacement therewith anddrivingly connecting said drive pulley to the carriage.

8. In combination with a tractor type of vehicle having a motive sourceof power rearwardly spaced from a for ward end of the vehicle, amaterial handling attachment comprising, a guide frame means pivotallyconnected adjacent a lower end thereof to said vehicle at said forwardend, mechanical control means operatively mounted on the vehicleintermediate said forward end and the source of power and operativelyconnected to the guide frame means for pivotal displacement thereofbetween adjusted positions, reversing gear means mounted on said guideframe means for pivotal displacement therewith, load lift means slidablymounted on the guide frame means and drivingly connected to thereversing gear means, flexible drive means drivingly connecting saidsource of power to the reversing gear means, belt tightener meansmovably mounted on the guide frame means and engageable with theflexible drive means to render the the reversing gear means operative inall adjusted positions thereof and reverse drive control means mountedon the guide frame means and projecting rearwardly therefrom above thereversing gear means for control thereof.

References Cited in the file of this patent UNITED STATES PATENTS1,280,090 Schrottky Sept. 24, 1918 1,526,621 Zaun 'Feb. 17, 19252,652,164 Tipps Sept. 15, 1953 2,785,818 Mercier et a1 Mar. 19, 19572,788,199 Ankersheil Apr. 9, 1957

